1. Field of the Invention
The present invention generally relates to a lighting unit, and more particularly to a lighting unit having light emitting diodes as light sources giving off lights to be dispersely reflected to illuminate a target, and also capable of using itself as a display unit.
2. Description of the Related Arts
Up until now, there have been proposed a variety of indirect-type light units which comprise a transparent plate having one side fashioned into an uneven surface or a reflective layer so as to serve as a planar light emitting member, and a plurality of light sources disposed on the side edges of the transparent plate and giving off lights to be scattered by the uneven surface or the reflective layer to substantially uniformly illuminate the entire transparent plate.
Such type of lighting units typically include a relatively large and powerful light sources such as a fluorescent lamp or a tungsten halogen lamp arranged on the side edges of the transparent plate. For example, large-scale ones are used as a device for lighting interior walls, while small-scale ones are utilized as a back light or a device for lighting a liquid crystal display surface on a small-sized computer or a word processor.
Such lighting units that are suitable for relatively uniformly illuminating a relatively large area have a tendency toward technical development to ensure, for example, more uniform overall lighting, enlargement in lighting area, or increased illuminance.
A small-sized device having a display surface such as a pocket calculator, a portable telephone set, or a portable game machine often uses a liquid crystal as its display surface. In this case, the conventional lighting unit is unsuitable to the above products having batteries as their power sources due to its large amount of power consumption. Therefore, most of the products do not employ such lighting unit.